Two-photon polymerization-based 3D-multi-electrode arrays for electrical monitoring of neuronal cells

3D-multi-electrode arrays (3D-MEAs) are needed to overcome the limitations of 2D-multi-electrode arrays (2D-MEAs) and enable the electrical characterization of 3D neuronal cultures in in vitro brain models, advancing the understanding of neurological disorders and paving the way to personalized medicine. The aim of this thesis was to overcome...

Speed-Power Improvement in High-Voltage Switches Employed in Multi-Electrode Arrays

In multi-electrode arrays (MEAs), for electrical recording and electrical stimulation, high voltage (HV) switches are employed to build an analog multiplexer to conduct either a HV stimulation signal from the pulse generator circuit to an electrode or a low-voltage noise-sensitive signal from the electrode to a recording stage. In this brief,...

High-density interconnect technology optimised for flexible implants

Electronic implants are becoming a valuable tool to explore and regulate neural activity, potentially overcoming neural disabilities that are still incurable. On the one hand, neural recording can provide tremendous insight into the neural system and the sometimes accompanied neural diseases. On the other hand, neural stimulation is necessary to...

The design of a steerable introduction shaft for electrode implantation on the dorsal root ganglion

Sensory nerve roots (DRGs) that emerge from the spinal cord can be stimulated with electrodes to prevent neuropathic pain. Proper functionality of DRG stimulation strongly depends on electrode placement, and conventional pre-curved introduction shafts limit DRG coverage of the implanted electrode lead. The goal of this thesis is to design an...

A Flexible Transparent Graphene Electrode Array for Spinal Cord Stimulation in Rats

Neural interface in the form of microelectrodes is used to monitor and treat spinal cord injury and other neurological disorders by the means of recording and stimulation. Despite the apparent result of these electrical interventions, understanding of the mechanism behind neural stimulation is still inadequate. The use of optical monitoring...

A compact matrix model for atrial electrograms for tissue conductivity estimation

Finding the hidden parameters of the cardiac electrophysiological model would help to gain more insight on the mechanisms underlying atrial fibrillation, and subsequently, facilitate the diagnosis and treatment of the disease in later stages. In this work, we aim to estimate tissue conductivity from recorded electrograms as an indication of...

Cytostretch, an Organ-on-Chip Platform

Organ-on-Chips (OOCs) are micro-fabricated devices which are used to culture cells in order to mimic functional units of human organs. The devices are designed to simulate the physiological environment of tissues in vivo. Cells in some types of OOCs can be stimulated in situ by electrical and/or mechanical actuators. These actuations can mimic...

Flexible active electrode arrays with ASICs that fit inside the rat’s spinal canal

Epidural spinal cord electrical stimulation (ESCS) has been used as a means to facilitate locomotor recovery in spinal cord injured humans. Electrode arrays, instead of conventional pairs of electrodes, are necessary to investigate the effect of ESCS at different sites. These usually require a large number of implanted wires, which could lead to...

Stretchable Micro-Electrode Arrays for Electrophysiology

A potential serious side effect of drugs is cardiotoxicity which can result in lethal heart arrhythmias. Cardiotoxicity has been the leading cause of drug withdrawals from the market in the past decades, and has been responsible for costly failures in late stage clinical trials. This highlights the unmet need in the pharmaceutical industry for...

Fabrication and characterization of an Upside-down CNT MEA

Over the last few years the need of new alternatives to traditional disease modelling, drug screening and toxicity tests has boosted the development of a new class of devices called Organ on Chip. These usually consist in a substrate or a well in which cells are cultured with the aim of differentiating them in a particular tissue lineage. With...

Flexible active electrode arrays with ASICs that fit inside the rat's spinal canal

Epidural spinal cord electrical stimulation (ESCS) has been used as a means to facilitate locomotor recovery in spinal cord injured humans. Electrode arrays, instead of conventional pairs of electrodes, are necessary to investigate the effect of ESCS at different sites. These usually require a large number of implantedwires,which could lead to...

Assessment of Cytostretch - A Heart-On-Chip device. Experiments on Cardiomyocytes

An organ-on-chip device, called Cytostretch (Philips NV), that is capable of mechanically stimulating cultured cells, is the subject of this study. The device comprises a microthin PolyDiMethylSiloxane membrane that is highly elastic, on which titanium nitride electrodes have been embedded. Its utility is projected in cardiac research to emulate...

Characterization of metals for Cochlear Implants

The need for Cochlear Implants (CI's) with improved functionality and quality requires new techniques to be used to manufacture the electrode array. Titanium nitride (TiN) is one of the contenders for use as metal in the future CI's, but its characteristics need to be verified, measured and tested. A metal should comply to certain requirements...

A Platform for Manufacturable Stretchable Micro-electrode Arrays

A platform for the batch fabrication of pneumatically actuated Stretchable Micro-Electrode Arrays (SMEAs) by using state-of-the-art micro-fabrication techniques and materials is demonstrated. The proposed fabrication process avoids the problems normally associated with processing of thin film structures on polydimethylsiloxane (PDMS), by first...